1. Field of The Invention
The present invention relates to a key usable as a spare key, and more particularly, to a key assembly for a car door lock, a building door lock and the like.
2. Description of The Prior Art
In general, keys for car door locks, building door locks and the like are held together by a ring type key holder and carried in a pocket. Such keys are usually made of thick material and comprise at their sides prominences and depressions which engage with prominences and depressions in key holes, as shown in FIG. 7, so that they are bulky. Therefore, most people do not like carrying many keys in their pocket. In particular, they do not carry spare keys any more. However, this often causes problems, such as when the car door is locked with keys left inside the car.